Storage device having an articulated cover fitting inner and outer containers

ABSTRACT

A container system includes an inner container adapted to nest inside of an outer container. A single cover sealingly engages both the inner and outer containers. The cover includes a first closure portion, a third closure portion, and an engagement portion. The third closure portion may be formed from an inside surface of at least a portion of the engagement portion. The outer container includes a second closure portion. The first closure portion of the cover is sealingly engageable with the second closure portion of the outer container to define a sealed storage area. The inner container includes a forth closure portion. The third closure portion of the cover is sealingly engageable with the forth closure portion of the inner container. The engagement portion of the cover is engageable with the engagement portion of a second cover to form a locked cover stack.

FIELD OF THE INVENTION

The present invention relates generally to storage devices having acover adapted to seal an inner and an outer container. Multiple coversof the plastic containers may be aligned together when stacked in afirst position and may be locked together in a second position.

BACKGROUND OF THE INVENTION

Rigid, thermoplastic food containers are generally known. Users oftenaccumulate a large number of these containers in different sizes andshapes. When not in use, the containers are often stored haphazardlyinto drawers. In this case, the unused containers take up a great dealof room, and finding a matching base and cover in a disarranged drawermay be difficult. To avoid this, some users stack the containers incabinets. While the bases of the containers usually nest and thereforetake up less room than in a disorganized drawer, it may still bedifficult to match a base with a cover. In addition, the covers may notstack and the covers may tend to topple down. When the containers are inuse to store food, the containers are often stacked one on top ofanother in cabinets or in a refrigerator. These stacks may beprecarious, and their fall may cause food to spill from the containers.Many users would find it desirable if the containers, whether empty orin use, could be stored in a manner space efficient, less precarious,and more structurally rigid. Related U.S. Patent Publication No.2009/0166369, describes a system of interlocking covers for sealableplastic containers and is hereby incorporated by reference in itsentirety.

During large-scale manufacturing, the covers may be transported in bulkbefore being separated out for individual packaging. During bulkhandling, manufacturers would find it desirable if the covers would forma stack stable enough to resist the vertical and lateral movementscaused by forces typically encountered during manufacturing operations.

Consumers often desire to carry two separate items in a storagecontainer. For example, a consumer may store a salad in one storagecontainer and salad dressing in a separate container. Conventionalsolutions for providing a single storage device for holding multipleitems have been proposed. U.S. Patent Publication No. 2007/0102319describes a one-piece container having a first vessel and a secondvessel permanently secured to and inside the first vessel. In thisdesign, the user may not be able to, for example, pour salad dressingout of the inner vessel without spilling the contents of the outervessel. U.S. Pat. No. 6,302,268 describes a container having an insertchamber that may release its contents into the container through a holein the bottom of the insert chamber. To fill the insert chamber, it mustbe removed from the lid of the container, filled, capped and inserted,cap side down, back into the container. When the insert chamber is notin use, it must remain in place in the lid of the container, else thelid of the container would have an opening and not seal the contentswithin the container.

The present invention has as a general aim to provide containers thatsatisfy both users and manufacturers.

Users would find it desirable to provide containers that advantageouslycreate a partial vacuum within the sealed storage area of the containerduring use. Still further, users would find it desirable a cover thatholds items in place within the container or that expands somewhat toaccommodate larger items. Still further, users would find it desirableto have covers that provide for cover interlocking while at the sametime allow for stacking of additional containers on top of the cover ofa first container. Still further, users would find it desirable for acover that may cover both an outer container and an inner container,fitting inside the outer container, simultaneously. What is needed is acontainer of improved flexibility that can provide these advantages.

SUMMARY OF THE INVENTION

In view of the foregoing, the present invention provides containerswhose covers can be stacked together in two different ways. First, thecovers can be stacked into an “aligned” stack. The aligned stackprovides enough structural rigidity for bulk handling duringmanufacturing. Second, the covers can be stacked into a “locked” stack.The locked stack provides even more structural rigidity than does thealigned stack and is useful when storing unused covers.

The present invention further provides a container whose cover maysecure an outer container while simultaneously securing an innercontainer positioned inside the outer container. The inner container maysealingly engage with an inner closure mechanism in the container cover.The outer container may sealingly engage with an outer closure mechanismin the same container cover. The inner closure mechanism may form aportion of a means for stacking the covers together.

In some embodiments, the cover may include a first closure portion, athird closure portion, an engagement portion, and an alignment portion.The outer container may include a second closure portion and the innercontainer includes a fourth closure portion. The first closure portionof the cover may be sealingly engageable with the second closure portionof the outer container to form a substantially sealed, leak-proof, andre-sealable storage area for items such as food. The outer surface ofthe alignment portion of the cover is engageable with the inner surfaceof the alignment portion of a second cover to form an aligned coverstack. The outer surface of the engagement portion of the cover may beengageable with the inner surface of the engagement portion of a secondcover to form a locked cover stack. The third closure portion of thecover may be sealingly engageable with the fourth closure portion of theinner container to define a substantially sealed, lead-proof, andre-sealable storage area for items such as food, condiments, or thelike. The third closure portion of the cover may be formed from theinner surface of the alignment and engagement portions of the cover.

Further, the covers of the present invention may include articulationelements that allow the covers to easily flex upwardly or downwardly,sometimes referred to as articulate, either alone or when engaged withthe base of the container. A protruding engagement portion of the covermay be articulated downwardly to the level of the top of the remainingportions of the cover.

The covers and bases (e.g., inner and outer containers) can beeconomically constructed from relatively thin-gauge plastic so that theuser can either wash them after use or dispose of them with the viewthat their purchase price allows them to be used as a consumable good.The container can be readily manufactured, for example, withconventional vacuum thermoforming equipment. The cover can be made froma semi-transparent material to ensure satisfactory visibility of thecontainer's contents. The container can be suitable for refrigerator,freezer, microwave, and machine dishwasher use.

The features of the present invention will become apparent to one ofordinary skill in the art upon reading the detailed description, inconjunction with the accompanying drawings, provided herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a container with a cover and a baseaccording to an embodiment of the present invention;

FIG. 2 is a partially cut-away view of a container, showing an innercontainer nested inside the base, according to an embodiment of thepresent invention;

FIG. 3 is a cross-sectional isometric view of a round container of theinvention;

FIG. 4 is a cross-sectional isometric view of the rectangular-shapedcontainer of FIG. 2;

FIG. 5 is a top plan view of the cover of FIG. 1;

FIG. 6 is a bottom plan view of the cover of FIG. 1;

FIG. 7 is an isometric view of the base of FIG. 1;

FIG. 8 is an isometric view of the inner container of FIG. 2;

FIG. 9 is a partial isometric sectional view with the engagement portionof the cover of FIG. 1 locking engaged with and engagement portion of asecond cover;

FIG. 10 is an isometric view of a container base;

FIG. 11 is a top plan view of the container base of FIG. 10;

FIG. 12 is a top plan view of a container cover;

FIG. 13 is a side sectional view of the container base of FIG. 10 andthe container cover of FIG. 12; and

FIG. 14 is an enlarged, detail view of a portion of FIG. 13.

DETAILED DESCRIPTION OF THE INVENTION

Turning to the drawings, wherein like reference numerals refer to likeelements, an embodiment of the present invention is illustrated in FIGS.1 through 8. A container 100 includes a continuous, flexible cover 102sealingly engaged to a outer container 104. In the example of FIGS. 1through 3, the container 100 is depicted as substantially circular intop plan view. In other embodiments of the present invention, forexample FIG. 4, the container 100 can have other shapes such asrectangular, square, or elliptical.

The cover 102 includes an engagement portion 106 that is lockinglyengageable with the engagement portion of a second cover (not shown inFIG. 1, see FIG. 9). As described more fully below with reference toFIGS. 10A through 13C, circumscribing the engagement portion 106 of thecover 102 is at least one articulation element 108. The engagementportion 106 of the Figures is depicted as circular but, as with theshape of the container 100 itself, other shapes are possible. In someembodiments, a standard shape and configuration of the engagementportion 106 is used with covers 102 of various shapes and sizes. Thisenhances storage flexibility by allowing different types of covers 102to be stored together in a locked stack.

The continuous cover 102 includes a first closure portion 310 (FIG. 6).The first closure portion 310 is sealingly engageable with a secondclosure portion 416 (FIG. 7) of the outer container 104. The firstclosure portion 310 of the cover 102 can be sealingly engaged with asecond closure portion 416 of the outer container 104 to provide aleak-resistant, re-sealable closure. When the first closure portion 310of the cover 102 and the second closure portion 416 of the outercontainer 104 are abutted and sealingly engaged with each other, thecover 102 and the outer container 104 define a substantially sealedstorage area within container 100 (FIG. 1).

The cover 102 includes a third closure portion 311 (FIG. 6) which may bean inner surface of the engagement portion 106. The third closureportion 311 is sealing engageable with a fourth closure portion 417(FIG. 8) of the inner container 105. The third closure portion 311 ofthe cover 102 can be sealingly engaged with the fourth closure portion417 of an inner container 105 to provide a leak-resistant, re-sealableclosure. When the third closure portion 311 of the cover 102 and thefourth closure portion 417 of the inner container 105 are abutted andsealingly engaged with each other, the cover 102 and the inner container105 define a substantially sealed storage area within the innercontainer 105.

As shown in FIGS. 2 through 4, the inner container 105, once sealed tothe cover 102, may fit inside the outer container 104 and the firstclosure 310 of the cover 102 and the second closure portion 416 of theouter container 104 may sealingly engage with each other. Thisconfiguration may provide a substantially sealed storage area within theinner container 105 removably nested inside a substantially sealedstorage area within the outer container 104.

The inner container 105 may have its own lid (not shown) that maysealingly engage with the inner container 105. In this configuration, anitem, for example, salad dressing, may be stored in the inner container105 and covered with its lid. When a user desires, the lid of the innercontainer 105 may be removed and the inner container may be sealinglyengaged with the cover 102 (FIGS. 2 through 4).

The inner container 105 may be pre-filled with an item, such as a dip,dressing, condiment, or the like, and sealed at the time ofmanufacturer. A user may unseal the inner container 105 and sealinglyengage the inner container to the cover 102 at the appropriate time. Forexample, salad dressing may be pre-filled into the inner container 105and sealed with a foil seal. When the user prepares a salad in the outercontainer 104, the user may remove the seal on the inner container 105,attach the inner container 105 to the cover 102 and seal the cover 102on the outer container 104. This configuration provides a convenient wayto carry a salad and salad dressing separately. When the user desires tomix the salad and dressing, they may simply remove the cover 102 fromthe outer container 104 and remove the inner container 105 from thecover 102. The user may then simply pour the contents of the innercontainer 105 onto the contents within the outer container 104.

In an alternate embodiment, the inner container 105 may be used to hold,for example, crushed ice. When the inner container 105 is sealed to thecover 102 and the cover 102 is sealed to the outer container 104, theice in the inner container 105 may help keep cold the contents withinthe outer container 104. The same concept may be used for keeping itemswarm. Alternatively, other substances may be stored in the innercontainer 105, such as an odor or moisture absorber. The inner container105 may be gas permeable to allow air to pass between the innercontainer and the outer container 105.

The size of the inner container 105 may vary depending on the desireduse. In some embodiments, the inner container 105 may, when sealinglyengaged to the cover 102 and the cover 102 is sealingly engaged to theouter container 104, come close to or contact the bottom of the outercontainer 104 (FIG. 2). In other embodiments, the inner container 105may, when sealingly engaged to the cover 102 and the cover 102 issealingly engaged to the outer container 104, be shorter and a gap 107may be present between the outer container 104 and the inner container105 (FIG. 3).

As shown in FIG. 7, the outer container 104 of the container 100includes a bottom 410 and a peripheral sidewall 412 extending upwardlyfrom the peripheral edge of the bottom 410. The top of the outercontainer 104 is open. The second closure portion 416 of the outercontainer 104, which, as noted above, is adapted to sealingly engagewith the first closure portion 310 of the cover 102 (FIG. 6), ispositioned at the open end of the peripheral sidewall 412 of the outercontainer 104. In one embodiment, the second closure portion 416 of theouter container 104 is a raised locking ring that extends from an upperedge of the peripheral sidewall 412 of the outer container 104.

More particularly with reference to the engagement portion 106, thecover 102 illustrated in FIGS. 1, 5, 6 and 9 includes the engagementportion 106 that allows the cover 102 to lockingly engage with theengagement portion 506 of a second cover 502 to form a locked stack ofcovers (FIG. 9). This locking feature makes the resultant stack ofcovers more structurally rigid and thus less precarious than atraditional, non-interlocked, stack of covers.

A shown in FIG. 9 the cover 102 is locked together with the second cover502 by their engagement portions 106 and 506 respectively. In theexample of FIG. 9, the engagement portion 106 of the cover 102 includesan upper protrusion 118 (see also FIG. 1) and a lower protrusion 120.Further, the engagement portion 506 of the second cover 502 likewiseincludes an upper protrusion 518 and a lower protrusion 520. Eachprotrusion 118, 518, 120, and 520 is convex on one side and concave onthe other. The lower protrusion 120 of the cover 102 fits over andreceives the upper protrusion 518 of the second cover 502, thus lockingthe covers 102 and 502 together. In this manner, the covers 102 and 502are held together and form a structurally stable cover stack. A thirdcover (not shown) may be lockingly engaged with the second cover 502, afourth cover with the third and so on to form a stack of any number ofcovers.

The engagement portion 106 can also be chosen to have a shape orotherwise include elements that provide an aligned or locked stack ofcovers 102 with rotational alignment. Rotation, as used herein, isdefined about an axis A (FIG. 1) normal to the plane formed byorthogonal midlines, i.e., first midline 205A and second midline 205B atthe top surface of the cover 102 as shown in FIG. 5. The origin of therotational axis is at the center point 207 at which the orthogonalmidlines intersect. For instance, shapes that inherently requirealignment prior to engagement or that may be self-aligning during theprocess of connecting engagement portions would be shapes with linear orcurvilinear sides, vertices or lobes such as triangular, square,rectangular, or multi-petal shapes. Additionally, the cover may have oneor more elements on or about the engagement portion that requirealignment prior to connection of engagement portions or elements thatmay be self-aligning during the process of connecting engagementportions.

Other embodiments of the engagement portion may include one or more ofthe following features to enable engagement: convex portions or ribs,concave portions or ribs, linear or curvilinear undercuts, discrete snapelements or buttons, interference fits, textured surfaces, or elementsthat modify surface friction or tackiness at or around the point ofengagement. The engaging areas that create a locking condition can becontinuous about the engagement portions or discretely segmented aboutthe engagement portions. In some embodiments, the force required toconnect the cover and the second cover may differ substantially from theforce required to disengage the covers. For instance, it may bebeneficial during manufacturing that the force needed to connect thecovers is less than the force required to separate the covers. As aresult, the covers are relatively easy to connect during manufacturing,yet they will lock securely and not undesirably separate during themanufacturing process. To accomplish this, the protrusions on theengagement portion may be designed where, for a given protrusion, theupper protrusion edge comprises a gradual taper whereas the lowerprotrusion edge comprises a more abrupt shape. For example, in oneembodiment, the shape of the protrusion may be similar to a barbed hookwith gradual taper on the upper edge of the barb that would impartlittle resistance during engagement and with an abrupt shape on thelower edge of the barb that would impart relatively high resistanceduring disengagement. Conversely, it may be beneficial to design theengagement portion so that the force that needs to be applied to connectthe covers is more than the force required to separate the covers, sincethe user may perceive that a high connecting force equates tosatisfactory locking integrity, whereas a weak connecting force may leadthe user to perceive that the cover stack lacks the integrity requiredto insure the expected organizational benefit. Thus, the high connectingforce provides the perceived benefit, yet a lower disengagement forcedoes not require that the user untowardly struggle during separation ofcovers. To accomplish this, the protrusions on the engagement portionmay be designed where, for a given protrusion, the upper protrusion edgecomprises an abrupt shape whereas the lower protrusion edge comprises amore gradual taper. For example, in one embodiment, the shape of theprotrusion may be a reversed barb with an abrupt shape on the upper edgeof the barb that would impart relatively high resistance duringengagement and with a gradual taper on the lower edge of the barb thatwould impart little resistance during disengagement. Furthermore, duringthe process where the user applies force to aligned covers in adirection normal to the general cover plane so as to lock the coverstogether, the engagement portion can provide tactile or audible feedbackupon locking In this way, the user would sense that the covers areconnected and that no further force need be applied

More particularly with regard to the first closure portion 310 and thesecond closure portion 416 forming the sealing engagement of the cover102 and the outer container 104, and to the third closure portion 311and the fourth closure portion 417 forming the sealing engagement of thecover 102 to the inner container 105, FIG. 6 is a bottom plan view ofthe cover 102 of FIG. 1. Referring to FIGS. 1, 6, 7 and 8, as notedabove, the cover 102 of the container 100 may sealingly engaged with theouter container 104 and the inner container 105 of the container 100.The cover 102 includes the first closure portion 310 (FIG. 6) in theform of receiver at the perimeter edge of the cover 102 adapted tosealingly engage the second closure portion 416 in the form of theraised locking ring at the top edge of the peripheral sidewall 412 ofthe outer container 104. The cover 102 further includes the thirdclosure portion 311 (FIG. 6) in the form of receiver at the perimeteredge of the inner surface of the engagement portion 106 adapted tosealingly engage the fourth closure portion 417 in the form of theraised locking ring at the top edge of the peripheral sidewall 413 (FIG.3) of the inner container 105. As a result, when the cover 102 and theinner container 105 are abuttingly engaged, a positive seal is formedbetween sealing surfaces around the perimeters of the inner container105 and of the cover 102. In this embodiment, the container 100 uses alocking rim design that includes both inside and outside seals. As wouldbe apparent to one of ordinary skill in the art however, the presentinvention can be embodied with a variety of closure designs includingouter closures and/or inner closures. Related U.S. Patent Publicationnumber 2008/0041850, co-owned with the present invention andincorporated in its entirety herein by reference, further describes theclosure portions. However, the closure portions described therein areexamples only, and many other types of closure portions could be usedwith the present invention.

The first and second closure portions 310 and 416 and the third andfourth closure portions 311 and 417 can be configured to be slightlydifferent in size to form an interference fit therebetween. Theinterference fit between the first and second closure portions 310 and416 and the third and fourth closure portions 311 and 417 can provide asealing engagement between the closure portions. As a result, when thepieces are abuttingly engaged, a positive seal can be formed between thefirst and second sealing surfaces around the perimeters of the outercontainer 104 and of the cover 102 and between the third and fourthsealing surfaces around the perimeters of the inner container 105 andthe cover 102. The sealing engagement of the closure portions can beaccompanied by an audible “snap” indicating that the container issecurely closed.

The outer container 104 and the inner container 105 can be made from anysuitable plastic with sufficient thickness to withstand withoutdeforming the heat of microwave cooking and of top-shelf dishwashing. Itshould also remain sturdy during lifting while laden with hot food. Theouter container 104 and the inner container 105 can be made from anysuitable plastic and can be made by any suitable technique, such asco-extrusion, lamination, injection molding, vacuum thermoforming, orovermolding. In one embodiment, the outer container 104 and the innercontainer 105 are formed from polypropylene. As with the cover 102, thenominal wall thickness of the outer container 104 and the innercontainer 105 can vary somewhat due to the manufacturing process.

The cover 102 of FIG. 1 can be constructed with a wall thickness thinnerthan that of a outer container 104. The cover 102 can be made from anysuitable plastic and can be made by any suitable technique, such asvacuum thermoforming processes described herein. In one embodiment, thecover 102 can be formed from polypropylene. Due to the vacuumthermoforming process, the wall thickness of the cover 102 can varyslightly over its nominal thickness. A cover 102 with a nominalthickness less than the nominal thickness of the outer container 104,however, reduces the cost of material for the container 100. Further,with a thinner cover 102, increased cover flexibility more easilyaccommodates the removal of the cover 102 from, and the sealingengagement with, the outer container 104. The cover 102 can maintainadequate flexibility for proper sealing even during typical freezertemperatures.

The container base 104 of FIGS. 10 and 11 includes a bottom 400 and asidewall 402 extending from the periphery of the bottom 400. The bottom400 includes a raised lower section 404 to accommodate the engagementportion 200 of a container cover 102 when containers 100 are stackedtogether. Just as the engagement portion 200 of the cover 102 of FIG. 12can include a central field 300, a similar field for a manufacturer'smark or for user information could be included in the raised portion 404of the base 104.

FIGS. 13 and 14 present embodiments of a container 100 whose cover 102is sealingly engaged with its base 104. FIG. 13 shows the cover 102cooperating with the base 104 to define a sealed storage compartment600. The cover 102 can be sufficiently flexible to allow a user tocreate a vacuum in the container 100 upon sealing. In order to create avacuum, the user could, for example, depress the cover 102 during theclosing of the container 100. A return force imparted upon the cover 102by the resiliency of the material of the cover 102 will urge the cover102 to return to its normal position, thereby creating a vacuum. Tofacilitate convenient sealing engagement of the cover 102 with its base104, the users can, at their discretion, apply downward force to onlythe engagement portion 200 of the container cover 102. The engagementportion 200 is located to accept and distribute the force to the firstclosure portion 700 of the cover 102 during sealing to the base 104. Theengagement portion 200 may also act as a convenient handle for graspingthe cover 102.

In the embodiments of FIGS. 13 and 14, the container 100 uses a lockingrim design that includes both inside and outside seals as will bedescribed. The present invention can be embodied with a variety ofclosure designs including outer closures and/or inner closures.

FIG. 14 depicts an embodiment of the closure portions used to engage thecover 102 with the base 104 of the container 100. The cover 102 includesa first closure portion 700 in the form of a raised locking ring. Thefirst closure portion 700 of the cover 102 can be engaged with a secondclosure portion 702 of the base 104 to provide a leak-resistant,re-sealable closure.

The first closure portion 700 includes an inner wall 704, a retentionbead 706, and an outer wall 708. The inner wall 704, the retention bead706, and the outer wall 708 define a first sealing surface, which ispart of the lower surface of the cover 102. The first closure portion700 can include one or more locking ridges 710. The outer wall 708extends between the retention bead 706 and a flange 712. The flange 712can provide a convenient gripping surface to facilitate the removal ofthe cover 102 from the base 104.

As illustrated in FIG. 14, the second closure portion 702 of the base104 is a raised locking ring that extends from an upper edge of thesidewall of the base 104. The second closure portion 702 includes aninner wall 714, a retention bead 716, and an outer wall 718. The innerwall 714, the retention bead 716, and the outer wall 718 define a secondsealing surface, which is part of the upper surface of the base 104. Thesecond closure portion 702 can include one or more locking ridges 720.The outer wall 718 extends between the retention bead 716 and a flange722. The flange 722 can provide a convenient gripping surface tofacilitate the removal of the cover 102 from the base 104.

The first and second closure portions 700 and 702 can be configured tobe slightly different in size to form an interference fit therebetween.The interference fit between the first and second closure portions 700and 702 can provide a sealing engagement between the closure portions.As a result, when the two pieces are engaged, a positive seal can beformed between the first and second sealing surfaces around theperimeters of the base 104 and of the cover 102.

The engagement of the first and second closure portions 700 and 702 canbe accompanied by an audible “snap” indicating that the container issecurely closed.

In the example of FIG. 14, the inner wall 704 of the first closureportion 700 of the cover 102 extends to the engagement portion 200. Thisengagement portion 200 includes an upper protrusion 724 and a lowerprotrusion 726. The cover 102 includes a ridge 728 on the outer wall 708of the first closure portion 700.

The cover 102 can be made by various plastic molding processes,including but not limited to vacuum thermoforming and injection molding.Vacuum thermoforming of the cover 102 is typically the most economicalmeans for forming the cover 102. As is well know in the art, vacuumthermoforming involves the heating a suitable plastic sheet of materialto a temperature at which the sheet becomes formable into a shape thatis set as the plastic sheet cools. As used herein, a suitable plasticsheet is a plastic sheet that may be readily used by the vacuumthermoforming process. The heated plastic sheet is made to conform tothe surface features of a single surface “male” tool by drawing theheated sheet of plastic to the surface of the tool by the force of avacuum applied to the tool. In vacuum thermoforming, the sealed airspace between the heated plastic and mold is evacuated to draw theheated plastic to contact the single male surface of the mold.

Typically, however, in vacuum thermoforming, the thickness of thefinished article formed by the process is nominally uniform. A sidecross-section view through the vacuum thermoformed article reveals asubstantially uniform thickness profile. The “bottom” surface of theheated plastic sheet that contacts the tool surface conforms to itsshape. The “top” surface of the plastic element formed in the vacuumthermoforming process does not contact a tool surface and generallyresides at a uniform distance from the bottom surface of the plasticarticle. Only nominal thinning of the plastic material occurs when itbends and stretches around curved mold features to conform to the pathof the curved surfaces of these features. As used herein, asubstantially uniform thicknesses in side cross-sectional profile is athickness in a plastic article that is not sufficiently variable topreclude its manufacture with typical prior art single male surfacevacuum thermoforming techniques. Conversely, a non-uniform thickness isa profile thickness in an article that varies enough to preclude themanufacture of the article with standard prior art vacuum thermoformingtechniques requiring instead other plastic molding techniques such asinjection molding.

Injection molding of a plastic article involves heating suitable plasticmaterial in the form of pellets or granules until a melt is obtained.The melt is next forced into a split-die mold, sometimes referred to asa split-die tool, where it is allowed to “cool” into the desired shape.Both the bottom surface and the top surface of the plastic article areformable by the split-die mold. Thus, articles may by formed by theinjection molding process that have side cross-sectional profiles ofvarying non-uniform thickness. After the plastic melt cools, thesplit-die mold is opened and the article is ejected. Since, the mold isseparable, undercut surface on the plastic article may be relieved fromthe split-die mold when it is opened. Injection molding, well know inthe art, is typically used to form plastic articles that have largeundercuts and substantially varying thicknesses in side cross-sectionalprofile. As used herein undercuts are said to be large if a moldedplastic article having undercut features is difficult or impossible toremove from a single-surface vacuum thermoforming mold after it isformed and cooled.

Since cover 102 as described, contains significant undercuts, such asincluded in upper protrusion 118 and lower protrusion 120 (FIGS. 1 and9) on the engagement portion 106 of the cover 102, injection moldingwould typically be required to form cover 102. Further, injectionmolding would typically be required to form articulation elements 108that are significantly thinner than the rest of cover 102.

The container 100 can be reusable, but it can also be constructedcheaply enough that consumers see it as a disposable item, withreplacement covers 102 and bases 104 available separately for retailsale. The outer container 104 and the cover 102 can be fabricated byvacuum thermoforming a clarified polypropylene homopolymer material. Inanother embodiment, the container 100 may be fabricated by vacuumthermoforming a clarified random copolymer polypropylene material. Otherplastic materials which would be suitable for fabricating the cover 102and the outer container 104 of the container 100 by vacuum thermoforminginclude PS (polystyrene), CPET (crystalline polyethylene terephthalate),APET (amorphous polyethylene terephthalate), HDPE (high densitypolyethylene), PVC (polyvinyl chloride), PC (polycarbonate), and foamedpolypropylene. The material used can be generally transparent to allow auser to view the contents of the container.

The container 100 may include a visual indication of closure between thecover 102 and the outer container 104 and/or between the cover 102 andthe inner container 105. The visual indication may be a color change inthe area where the cover 102 engages the outer container 104 and/or theinner container 105. In one embodiment, the first closure portion 310 onthe cover 102 may be a first color and the second closure portion 416 onthe outer container 104 may be a second color. When the closure portionsare engaged, the first and second colors produce a third color which isvisible to the user to indicate that the container 100 is sealed.

The container 100 may include a rough exterior surface to reduceslipping and to improve grasping by the user, especially if the user'shands are wet or greasy.

The container 100 may include a self-venting feature. The pressure inthe sealed container 100 may increase when the sealed container 100 andcontents are heated in a microwave oven. Thus, the cover 102 may includea self-venting mechanism, which opens when the pressure in the container100 exceeds a predetermined value.

The container 100 may be divided to separate foods in the container. Adivider may be integral with the container 100 or may be a separatecomponent. Either the outer container 104 only may include a divider orboth the outer container 104 and the cover 102 may each include adivider. The divider located in the cover 102 may only partially engagethe divider in the outer container 104 so as to provide splashprotection, or it may fully engage the divider in the outer container104 to provide varying degrees of inter-compartmental leak resistance.

The container 100 may include a strip indicating the temperature of thecontainer 100 and its contents.

The use of the terms “a,” “an,” “the,” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. Recitation of ranges of values herein are merely intended toserve as a shorthand method of referring individually to each separatevalue falling within the range, unless otherwise indicated herein, andeach separate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate the invention and does not pose alimitation on the scope of the invention unless otherwise indicated.

While the invention is described herein in connection with certainpreferred embodiments, there is no intent to limit the present inventionto those embodiments. For example, those of skill in the art wouldrecognize that may be formed such that the vertex of the articulationelement 108 is above the top of the cover 108, that is the articulationelements 108 may be pointed upwardly. It is recognized that variouschanges and modifications to the described embodiments will be apparentto those skilled in the art upon reading the foregoing description, andthat such changes and modifications may be made without departing fromthe spirit and scope of the present invention. Skilled artisans mayemploy such variations as appropriate, and the invention may bepracticed otherwise than as specifically described herein. Accordingly,the intent is to cover all alternatives, modifications, and equivalentsincluded within the spirit and scope of the invention. Moreover, anycombination of the above described elements in all possible variationsthereof is encompassed by the invention unless otherwise indicatedherein or otherwise clearly contradicted by context.

1. A container comprising an outer container, an inner container, and acover, the outer container including: a bottom; a peripheral sidewallextending from said bottom; an open top; and a second closure portion,the inner container fitting inside the outer container, said innercontainer including: an inner container bottom; an inner containerperipheral sidewall extending from said inner container bottom; an innercontainer open top; and a fourth closure portion, the cover including: afirst closure portion, said first closure portion being sealinglyengageable with said second closure portion of said outer container suchthat when said first closure portion and said second closure portion areengaged with each other, said cover and said outer container define afirst substantially sealed storage area; and a third closure portion,said third closure portion being sealingly engageable with said fourthclosure portion of said inner container such that when said thirdclosure portion and said fourth closure portion are engaged with eachother, said cover and said inner container define a second substantiallysealed storage area.
 2. The container of claim 1 further comprising: anengagement portion of said cover, said engagement portion beingengageable with a similar engagement portion of another cover; and atleast one articulation element on said cover.
 3. The container of claim2, wherein an inside surface of said engagement portion forms at least aportion of the third closure portion.
 4. The container of claim 2wherein said at least one articulation element circumscribes saidengagement portion of said cover.
 5. The container of claim 4 whereinthe bottom of said outer container includes a raised lower section. 6.The container of claim 1 wherein said first closure portion includes aninner wall, a retention bead, and an outer wall.
 7. The container ofclaim 6 wherein said inner wall includes one or more locking ridges. 8.The container of claim 7 wherein said outer wall extends between saidretention bead and a flange.
 9. The container of claim 8 wherein theouter wall includes a ridge.
 10. The container of claim 1 wherein thethird closure portion is formed in a central region of said cover. 11.The container of claim 1 wherein said inner container is formed of a gaspermeable material.
 12. The container of claim 1 wherein the firstclosure portion is sealingly engageable with a second closure portion ofsaid outer container such that when said first closure portion and saidsecond closure portion are engaged with each other, said cover and saidouter container define a first substantially sealed storage area,regardless of a presence or an absence of the inner container from thecontainer.
 13. A container comprising: an inner container; an outercontainer; and a cover, wherein said inner container and said outercontainer are adapted to sealingly engage with said cover; and the innercontainer nests within said outer container when said inner containerand said outer container are both sealingly engaged with said cover. 14.The container of claim 13 wherein said cover comprises: a first closureportion, said first closure portion being sealingly engageable with asecond closure portion of said outer container such that when said firstclosure portion and said second closure portion are engaged with eachother, said cover and said outer container define a first substantiallysealed storage area; and a third closure portion, said third closureportion being sealingly engageable with a fourth closure portion of saidinner container such that when said third closure portion and saidfourth closure portion are engaged with each other, said cover and saidinner container define a second substantially sealed storage area. 15.The container of claim 14 further comprising: an engagement portion onsaid cover, said engagement portion being engageable with an engagementportion of a second cover; and at least one articulation element on saidcover, wherein an inside surface of said engagement portion forms atleast a portion of said third closure portion.
 16. The container ofclaim 15 wherein said at least one articulation element circumscribessaid engagement portion of said cover.
 17. The container of claim 16,wherein said third closure portion is formed in a central region of saidcover.
 18. The container of claim 14, wherein said first closure portionis sealingly engageable with said second closure portion of said outercontainer independently of said third closure portion being sealinglyengaged with said fourth closure portion of said inner container.
 19. Acontainer including an outer container, an inner container, and a cover,the outer container comprising: a bottom; a peripheral sidewallextending from said bottom; an open top; and a second closure portion,the inner container, said inner container fitting inside the outercontainer, said inner container comprising: an inner container bottom;an inner container peripheral sidewall extending from said innercontainer bottom; an inner container open top; and a fourth closureportion, the cover comprising: a first closure portion, said firstclosure portion being sealingly engageable with said second closureportion of said outer container such that when said first closureportion and said second closure portion are engaged with each other,said cover and said outer container define a first substantially sealedstorage area; a third closure portion, said third closure portion beingsealingly engageable with said fourth closure portion of said innercontainer such that when said third closure portion and said fourthclosure portion are engaged with each other, said cover and said innercontainer define a second substantially sealed storage area; anengagement portion, said engagement portion being engageable with anengagement portion of a second cover; and at least one articulationelement on said cover, wherein an inside surface of said engagementportion forms at least a portion of the third closure portion.
 20. Thecontainer of claim 19, the first closure portion is sealingly engageablewith said second closure portion of said outer container independentlyof said third closure portion being sealingly engaged with said fourthclosure portion of said inner container.